Interlocking plug and cap



July 29, 1930.

H. HUBBELL, JR

INTERLOCKING PLUG AND CAP Original Filed June 1925 l i'lllllllllllll llllli Eluoentoz Patented July 29, 1930 UNITED STATES PATENT-OFFICE HARVEY EU BBELL, 38., O1 BRIDGEPORT, CBNNEGTICUT, ASSIGNOB TO HARVEY HUB- ZBELL, INCORPORATED, OF IBRIDGEPORT NECTIQUT CONNECTICUT, A CORPORATION OF GON- m'rnnnoo'xme' rnue AND on Application filed .Tune 8, 1925, Serial No. 85,424. Renewed December 20, 1929.

This invention relates'to devices for connecting the leads of electrical attachments to a source of power, and has for an object to provide an improved connection of this character which willnot become accidentally disconnected, but in which, although the'members are positively secured together in normal operation, they may be quickly and easily separated for disconnecting the attachment.

With the foregoing and other objects in view, I have devised the construction illustrated in the accompanying drawing forming a part of this specification, similar reference characters being employed throughout the 1; various figures to indicate corresponding elements. In this drawing,

Fig. 1 is a side elevation of a device embodying my invention with the two members in connected relation and with portions of I; the wall of one of the members broken away to show how they are locked together.

Fig. 2 is a side elevation of the device.

Fig. 3 is an end view of the plug member.

Fig. 4 is an end view of the end portion of 85 the plug member showing the contacts mounted thereon.

Fig. 5 is a transverse section substantially on line 5--5 of Fig. 1 showing the elements in locked position. 30 Fig. 6 is a transverse'section substantially on line 66 of Fig. 2 showing the elements in locked position.

Fig. 7 is an end view of the cap member.

Fig. 8 is a side elevation thereof.

Fig. 9 is a side elevation of the cap looking from the right of Fig. 8, and

Fig. 10 is a side-elevation of the end member of the plug shown in Fig. 4 and with the cylindrical portion of the plug removed.

I have illustrated my invention as applied to a plug and cap for use 1in flexible connections leading to electrical attachments or portable devices, but it is to be pnderstood that the plug is used merelyfor the purpose of il- 5 lustration and the invention. is'equally adapted for use in stationary receptacles, current taps and the like. 4

In the embodiment shown' the plug comprises an insulating body member made in 6 two sections 10 and 11 the section 10 being a substantially cylindrical section and the end section 11 being preferably shaped to correspond with the cap which is intended to be used therewith to give a neater and more attractive appearance. When assembled the two sections are connected by the screws 12 passlng through the section 10 and threaded into members 13 molded in the cap, and thus when assembled thetwo sections form a unitary structure. The making of the plug in sections facilitates the manufacture and the assembling and disassembling of the various elements. It also allows separation of the sections for connection of the lead wires to the binding posts connected to the contacts carried by the plug.

Mounted in the end section 11 is a pair of spring contacts 14. In the present construct1on they are secured to the section by screws 15 and carry binding posts 16 by means of which they are connected to the lead wires 17 in a cable 18 leading from a suitable source of power. These contacts comprise substantially flat body portions 19 curved or bent upon themselves. as shown at 20, to form two substantially plane portions 21 and 22 arranged at an obtuse angle to each other, as indicated in Figs. 4, 5 and 10, and these are the portions which are engaged by the contact fingers of the cap. The cylindrical section 10 isprovided with recesses or chambers 23 leading from its inner end in which these contacts are located when the sections are secured together as shown in Fig. 1, and at its opposite end the section 10 is provided with openings 24 leading to these recesses for the entrance of the contact fingers of thecap. These openings are curved, as shown in Figs. 3, 5 and 6 so as to be in alignment with both portions 21 and 22 of the contacts, and these openings are of less length than the recesses or chambers 23 so that shoulders 25 are formed at the inner end of the openings for a purpose presently to be described.

The cap comprises an insulating body v95 member 26 in which contact fingers 27 are mounted. The cap has an' openin 28 for passageof the leads 29 in the flexi 10 cable 30 leading to any suitable electrical device to which it is desired to. transmit power.

The contact fingers are secured in the cap by suitable rivets 31 and are connected to the leads 29 by suitable bindin posts 32. The fin ers comprise substantia 1y strai ht, flat body portions 33 and substantlally p ain lateral portions 34 integral with the body portion at one edge thereof. These two portions are arranged at an obtuse angle to each other, as shown in Fig. 7, and'which angle is substantially the same as that between the portions 21 and 22 of the contacts in the plug, for a purpose which will later be described. It will be apparent from Figs..7, 8 and 9 that when assembled in the cap the lateral portion 34 of one finger extends in the opposite direction from the lateral portion of the other finger, although the two fingers are of exactly the same construction. It is also to be noted that the lateral portion 34 is shorter than the body portion 33 so as to provide a shoulder 35 extending to one side of and intermediate the ends of the fingers.

The operation is as follows When it is desired to make the electrical connection between the two cables 18 and 30 the contact fingers 27 of the cap are inserted in the openings 24 in the free end of the plug, as indicated in dotted lines (D) in Figs. 5 and 6, and are pushed in as far as they will go bringing them into engagement with the contacts 14 in the cap. Thus the electrical cir-. cuit is completed and the members act the same as' the ordinary plug and cap, the cap being easily separated from the plug by pulling it outwardly away from the plug in the usual manner. It very often happens, however, that in use some one will catch their foot on the cord, or in moving the attachment the strain on the cord will separate the plug and cap thus breaking the electrical connection. With the construction illustrated, however, this accidental disconnection may be prevented. If, after the fingers 27 are inserted in the openings 24 to engage the contacts 14, the cap 26 and the plug 10 are given relatively rotary movements, the cap moving counterclockwise as viewed in Fig. 5, and clockwise as viewed in Fig. 6, the lateral portion 34 of the fingers 27 will be moved behind the shoulders 25 in the recesses 23 in the plug, and therefore, if there is a strain tending to pull the cap from the plug the shoulder 35 will engage the shoulder 25 and lock the cap to the plug. The fingers 27 will now be in the position shown in Fig. 1 and indicated in full lines in Figs. 5 and 6. The angular arrangement of the two portions 21 and 22 of the contacts 14 and the portions 23 and 24 of the fingers 27 tend to prevent relative rotary movement of the cap and plug in the opposite direction. As these portions are substantially plane portions and because of their angular relation, when this relative turning movement is made the spring contacts 14 must yield laterallv. Thus the cap and plug are yieldingly held in looking position, but if it is desired to separate the cap from the pluglall that is necessary is to turn the cap in t e opposite direction, that is, clockwise as viewed in Fig. 5 or counterclockwise as viewed in Fig. 6. This movement will carry the portions 33 and 34 of the contact fingers 27 again into alignment with the openings 24 in the end of the plug and the shoulder 35 away from the shoulder 25. The cap may then be removed by pulling it outwardly in a direction longitudinally away from the plug.

It will be apparent that this locking arrangement is not limited for use with a portable plug as indicated, but is equally adapted foruse with wall receptacles, current taps, and so forth. It is also to be noted that the plug may be used with the ordinary standard cap having plain, fiat contact fingers with no locking action, and that contact may be made with this plain cap in either position,'that is, the fingers of the cap may engage either the main portions 21 or the lateral portions 22 of the spring contacts 14.

Having thus set forth the nature of my invention, what I claim is:

1. In combination, an insulating body member having sockets enclosing stationary contact members and openings leading to said contacts, and a cap having contact fingers for insertion in said openings to engage the contact members by a relative longitudinal movement of the cap and body member, said body member and fingers being provided with coacting locking means to prevent separation of the members and mounted to be connected and released by a relative turning movement of said cap and body member while the contact fingers are in engagement with the contact members.

2. In combination, an insulating body member carrying spaced stationary contacts, a cap carrying spaced contacts to engage those of the body member by a relative 1ongitudinal movement of the cap and body member, and interlocking means to prevent separation of the cap and body member mounted to become effective and ineffective by a relative turning movement between the cap and body member while the contacts of the cap and body members are continuously in engagement.

3. In combination, an insulating body member, a plurality of stationary contacts carried by said member, said member having openings leading to the contacts, and a cap having contact fingers for insertion in said openings to engage the contacts by a relative longitudinal movement of the cap and body member, said fingers having proj ecting portions at one side thereof to engage the wall of the body member at one side of the openings to prevent separation of the cap and body member, said openings being of sufiicient width to allow lateral movement of the fingers to bring the projecting (portions in alignment with the wall of the b contacts carried by said member'having two substantially flat portions extending at an angle to each other, said body being provided with openings leading to said contacts and so shaped as to be in alignment with both of said portions, and a cap having contact fingers adapted to enter the openings and each adapted to engage either of said portions of the corresponding contact and provided with a shoulder arranged to move to-one side of the openings to engage the wall of the body and prevent separation of the body and cap.

5. In a device of the character described, an insulating body member having recesses, a plurality of contacts carried by said member in said recesses having two substantially flat portions extending at an angle to each other and longitudinally of said member, said body being provided atone end with narrow arcuate slots leading to said contacts and arrangedin the same or concentric circles, each being in alignment with both portions of a contact, and the recesses being of a greater extent than the slots to provide looking shoulders at one end of the-slots to cooperatewith projecting shoulders on the contact blades of an attachment plug cap.

6. In a device of the character described, an insulating body member, having recesses, and spring contact members in said recesses comprising two longitudinally extending substantially plane portions arranged at an obtuse angle to each other, the body member being provided with narrow arcuate slots leading, to saidcontacts in a direction longitudinally thereof and arranged in the same or concentric circles, each being in alignment with one end of both portions of a contact, and the recesses being of greater extent than the slots to provide locking shoulders at one end of the slots to cooperate with laterally extending shoulders on the blade contacts of an attachment plug cap.

7. In a devlce of the character described, an insulating body member having recesses, and contact mem ers in said recesses comprising a supporting portionv curved backwardly upon itself to provide a spring contact portion extending in the same general direction as the supporting portion, said contact portion comprising two substantially plane portions arranged at an obtuse angle to each other, said body member being provided with openings leading to the recesses for entrange of contact fingers to en age said plane port1ons,,said openin s extend tion longitudinally 0 said contact portions.

8.. Ir. 'a device of the character described,

y mem- 111g in a direc-* an insulating body member having recesses, spring contact members in said recesses comprising two longitudinally extending substantially plane portions arranged at an obtuse angle to each other, the body member being provided with openings leading to said contacts and in alignment with said portions, and a cap having contact fingers arranged to enter said openings to engage the contacts by a relative longitudinal movement of the cap and the bod shoulders to engage the wall of the body at the inner ends-of the openings by a relative rotary movement of the cap and body to prevent separation of the body and cap.

,9. In a device of the character described, an insulating body member havin recesses, spring contact members in sai recesses comprising two longitudinally extending substantially plane portions arranged at an obtuse angle to each other, the body member y member and provided wit being provided at onexend with openings and in alignment a cap having an insulating body, and contact fingers mounted on-said body so as to be insulated from each other and projecting from said body in spaced relation, said fingers each having a substantially plane body portion and a substantially plane portion projecting laterally from one side edge of the body portion and extending longitudinally thereof, said portion being also arranged at an obtuse angle to the body portion and of less length than the body portion to provide a shoulder between the ree end of the finger and the insulating body and said fingers being ar-' ranged with their concave-sides opposed to each other. V g I In testimony whereof I aflix my si ature.

-HARVEY HUBBEL JR. 

